1. Field of the Disclosure
The present disclosure relates to crimping systems and methods for forming longitudinally curved building panels of sheet material that can be connected together to form free-standing, self-supporting buildings. More particularly, the present disclosure relates to panel crimping machines and associated methods for crimping (corrugating) such a building panel so as to impart a longitudinal curve to the building panel along its length.
2. Background Information
Methods and machines are known in the art for forming building panels of desired shapes made from sheet material, e.g., galvanized steel sheet metal. Such building panels can be attached side-by-side to form self-supporting building structures by virtue of the strength of the building panels themselves. That is, such interconnected building panels can exhibit a moment of inertia suitable to provide enough strength under applied loads (e.g., snow, wind, etc.) so that supporting beams or columns within the building structure are unnecessary. In other words, the interconnected building panels themselves may form a load-bearing roof portion and a load-bearing wall portions of a self-supporting building without the need for supporting beams, columns, joists and the like. FIGS. 1-3 illustrate exemplary shapes of self-supporting metal buildings. These exemplary building shapes include double-radius (or two-radius) style buildings, an example of which is shown in FIG. 1, gable style buildings, an example of which is shown in FIG. 2, and circular or arch style buildings, an example of which is shown in the example of FIG. 3. In the exemplary buildings illustrated in FIGS. 1-3, building panels that include longitudinally curved building panels are used to form the side and roof sections, and substantially straight building panels or other materials are used to construct the flat end-wall sections.
As is known in the art, building panels of a desired cross-sectional shape may be formed from steel sheet metal using a panel forming apparatus having particular configurations of steel rollers. Flat sheet metal is introduced into the panel forming apparatus, and the rollers contact and deform the sheet metal as it passes through the panel forming apparatus, such that the building panel emerges with a desired cross sectional shape.
The resulting building panel, having been shaped in cross section, can then be curved (arched) in the longitudinal direction (perpendicular to the transverse, cross-sectional direction) using a panel curving apparatus. One type of curving apparatus utilizes rollers having crimping blades that indent the building panel to impart transverse corrugations (or cross corrugations) of suitable depths into the panel as the building panel passes through the apparatus, so as to provide the longitudinal curve to the building panel. Exemplary crimping machines of this type are disclosed in U.S. Pat. Nos. 3,902,288, 4,364,253, 4,505,143, 5,249,445, 6,820,452 and 6,722,087, and 8,033,070, the entire contents of each of which are incorporated herein by reference.
An exemplary conventional building panel having such transverse corrugations is shown in FIG. 4 as described in U.S. Pat. No. 3,902,288. The building panel illustrated in FIG. 2 is generally box-shaped and has a base or bottom portion 22, a pair of spaced upright side portions 23 and 24 projecting upwardly from the opposite marginal edges of and in a direction transverse to the flat bottom portion 22, and an upper in-turned flange portion 25 projecting inwardly from the upper marginal edge of and in a direction transverse to the side portion 23. An upper out-turned flange portion 26 projects outwardly from an upper marginal edge of and in a direction transverse to the side portion 24 and has a down-turned terminal portion 26a at the outer marginal edge thereof. The in-turned flange portion 25, has a terminal section 25a bent toward the side portion 23 to provide a reverse bend or fold and a double thickness. The out-turned flange portion 26 is bent downwardly to provide generally U-shaped connecting channel with a bottom opening. The bottom opening formed by the out-turned flange portion 26 is of greater width than the in-turned flange portion 25 so that it will receive the in-turned flange portion of the next adjacent panel directly through the bottom opening in order to connect adjacent panels together.
Such panels can be curved in the longitudinal direction by forming transverse corrugations in the center portion 22 and in the side portions 23 and 24, the corrugations being comprised of a series of alternative grooves and ridges. Grooves and ridges forming transverse corrugations in the side portions 23 and 24 are designated by numerals 31 and 32, respectively. Grooves and ridges forming transverse corrugations in the center portion are designated by numerals 33 and 34, respectively.
The transverse corrugations can be formed in both the center portion and side portions of the building panel using a panel crimping machine with pairs of crimping rollers that have opposing crimping blades to impart the transverse corrugations.
The present inventor has observed a need for an improved drive system for a panel crimping machine that can better maintain proper timing between a pair of crimping rollers if the separation distance between the crimping rollers is changed, and the exemplary systems and approaches described herein may address that need.